Detonating means securing device



Feb. 23, 1955 R. G. NELSON 3, 7 0

DETONATING MEANS SECURING DEVICE Filed Nov. 23, 15960 2 Sheets-Sheet 1 Feb. 23, 1965 R. G. NELSON DETONATING MEANS sscuamc; DEVICE 2 Sheets-Sheet 2 Filed Nov. 23. 1960 F IGA F IG. 6

INVENTOR. Richard (5. Nelson United States Patent Ofiice Patented Feb. 23,: 1955 3,170,400 DETONATING MEANS SECURING DEVICE Richard Grofi Nelson, Tamaqua,'Pa., assignor to Atlas Chemical Industries, Inc., Wilmington, Del., 21 corporation of Delaware Filed Nov. 23, 1960, Ser. No. 71,195 5 Claims. (Cl. 102-44 The present invention relates to a detonating means securing device and to an explosive assembly equipped with such device. Specifically, the present invention relates to a device to secure an electric detonator or booster charge within a base explosive charge and to a blasting assembly comprised of an explosive charge having an electric detonator or booster charge secured therein by the securing device.

Base explosive charges are commonly equipped with a perforation or small hole called a well, which facilitates the insertion of a detonating means within the charge. When a suitable detonating means is positioned in the well of an explosive charge proper initiation of the explosive is assured. Loading and tamping operations after the detonating means has been positioned in the well must be carefully carried out in order to insure that the detonating means remains in place, as displacement of the detonating means frequently results in a misfire. The present invention provides a securing means which insures that once the detonating means is positioned within the Well it is held secure against outward displacement. The present invention provides a means of securing a detonating means within an explosive charge without resorting to the use of metal components which may be considered objectionable from a safety standpoint.

As used herein the term filament tape is defined to include tapes wherein the tape is reinforced by a layer comprised of a plurality of substantially continuous strands, or filaments, of a strong, high tenacity material. In commercially available tapes which are suited to carry out this invention thefilaments are generally disposed parallel to the edges of the tape. The tape mayhave shorter spaced cross strands disposed at an angle to the substantially continuous strands. The substantially continuous strands may be made of glass, cellulose acetate, cellulose propionate, superpolyarnides of the nylon type, rayon, silk, or vinylidene chloride interpolymers, e.g., with vinyl chloride and/or acrylonitrile. The spaced cross strands may be woven or nonwoven with the substantially continuous strands. Examples of filament tapes suited to carry out the present invention are described in the following US. patents: 2,750,314; 2,750,315 and 2,744; 041.

According to the present invention a means of securing a detonating means in the well of an explosive charge is provided by the utilization of a piece of filament tape. Filament tapes having a coating of pressure sensitive adhesive on one side and having a layer of substantially continuous filaments predominantly disposed in a direction parallel to the edges of the tape are eminently suited to use in the present invention. In a preferred embodiment of the present invention, a length of tape is placed over the well of an explosive charge with the ends of the tape extending beyond the opening of the well in two directions. The extending ends of the tape are secured to the explosive charge on either side of the well to form an explosive assembly. It is preferred that the well in the explosive charge be of an adequate depth to receive the entire detonating means. A small slit, approximately equal in length to the width of the detonating means to be used, is cut through the tape along a direction parallel to fuse threaded therethrough and secured v by a knot.

tape on the explosive charge and then slit the tape at a point just over the well.

To form an armed blasting assembly, the detonating means is inserted into the well of the explosive charge equipped with the securing means by passing the detonating means through the slit in the filament tape. After the detonating means has been inserted into the well, the filaments of the tape tend to spring back to their original \position thereby securing the detonating means against Outward displacement caused by movement of the charge or by forces tending to pull the detonating means out of the well.

It will be appreciated that the tape, positioned over the well of the explosive charge, protects the well against entry of foreign materials, such as dirt or rock chips which could create a hazard in the arming operation.

Although it is not a preferred form .of the present invention, securing action may also be carried out by utilization of two lengths of filament tape in juxtaposition which are secured to the explosive charge and positioned so that the juncture of the two lengths of tape lies immediately over the well. A detonating means may then be inserted through the tape juncture at a point just over the well and is thereby secured in the well by the overlying tape.

The term detonating means as used herein will be understood to include electric detonators, detonating fuse, and booster or primer charges. In any case, the base xplosive charge is perforated to receive the, detonating means therein. In case a length of detonating fuse is to be secured a knot is placed in the end-to be received by the base explosive charge and the knot passed through the slit in the tape securing means. The present invention facilitates the secure placement of booster or primer charges within a base charge. Booster or primer charges utilized with the securing device of the present invention may be perforated to receive an initiating means, such as an electric detonator Or a length of detonating fuse, therein. In case a length 'of detonating fuse is utilized along with a booster or primer charge, the charge is preferably perforated so that the detonating fuse may be threaded therethrough and secured from outward displacement therefrom by a knot placed in the end extendedcharge and the combination secured within the base charge.

The invention may be more clearly understood by refe-rence to the accompanying drawings whichwill serve to illustrate typical embodiments of the present invention and which like parts are identified by similar reference numbers throughout the several views,

FIGURE 1 is a perspective view showing an explosive charge equipped with a length of filament tape and an electric detonator prior to insertion into the charge,

v FIGURE 2 is a perspective view showing an armed blasting assemblycomprised of the explosive charge of FIGURE 1 after the inertion of a detonator therein,

FIGURES 3 and 4 are perspective views comparable to IGURES 1 and 2, except that they show a securing means comprised of two lengths of filament tape in juxtaposition over the well in the explosive charge.

FIGURE 5 is a perspective view showing an explosive charge equipped with a length of filament tape and a' sleeve-type booster charge having a length of detonating from withdrawal FIGURE 6 is. also a perspective view showing the explosive charge of FIGURE 5 after insertion of the booster charge shown in FIGURE 5. g I

Referring to FIGURE 1 in detail: An explosive charge is shown as a generally cylindrical cartridge 11. The explosive charge will generally consist of a suitable amount of a common detonating explosive such as dynamite, RDX, Composition B or PETN. The explosive charge may be in the form of a solid or powder and may be either molded or packed in a cartridge. The. charge has a surface suited to secure a length of suitable filament tape. The charge is equipped with a well 13 of a length sufficient to completely receive an electric detonator. Well 13 is covered with a length of adhesive filament tape 1? extending beyond the top of the' well and secured to the side wall of explosive charge 11 and forms an explosive assembly. Tape 17 has a slit 15 positioned parallel to the direction of the predominant filaments 21 in the tape. An electric detonator 19 having leg Wires 23 and 23' is shown in position to be inserted into well 13 through slit 15 in tape 17.

FIGURE 2 shows the explosive assembly of FIGURE 1 after the electric detonator is inserted and secured therein by tape 17 to form an armed blasting assembly.

Referring now to FIGURE 3 in detail: An explosive charge 11, having a well 13 is equipped with a securing means comprised of two lengths of filament tape 17 and 17". Tape lengths 17' and 17" are in juxtaposition with the side juncture of the lengths lying immediately over well 13. The ends of tapes 17' and 17" are secured to the side wall of explosive charge 11. An electric detonator 19 having leg wires 23 and 23' is shown in position to be inserted into well 13 through the juncture of tapes 17 and 17" at a point immediately over well 13.

FIGURE 4 shows the explosive charge of FIGURE 3 after the detonator has been inserted and secured within the explosive charge 11 to form an armed blasting assembly.

Referring now to FIGURE 5 in detail: An explosive charge 11 is equipped with a well 13 of suflicient length to completely receive a booster assembly comprised of booster 25 and a length of 50 grain detonating fuse (50' grains of PETN per foot) 27 extending therethrough and terminating in knot 29. A booster arrangement is usually utilized to initiate relatively insensitive explosive charges, such as mixtures containing a high percent by weight of ammonium nitrate sensitized with a carbonaceous material. Generally such mixtures are insensitive to either a #6 blasting detonator or 50 grain detonating fuse and require a booster or primer charge for initiation. The explosive charge in booster 25 is a detonator or detonating fuse sensitive high explosive. for example, RDX, Composition B, or PETN. Well 13 is covered with a length of adhesive filament tape 17 extending beyond the top of the well and secured to the side wall of base explosive charge 11 to form an explosive assembly. Tape 17 has a slit 15 positioned parallel to the predominant filaments 21 in the tape. FIGURE 6 shows the explosive charge of FIGURE 5 after the booster assembly is inserted and secured therein by tape 17 to form an armed blasting assembly.

As a result of this invention, it will be noted that an explosive assembly may now be produced that is equipped with a well adapted to receive a detonating means and a means of securing the detonating means Al therein which entails no complicated or undesirable components and which facilitates easy packing and storage. The explosive assembly is adapted to quickly and easily receive and secure detonating means therein to form an armed blasting assembly.

What is claimed is: g

1. An explosive assembly comprising an explosive charge containing a well, said well being of a size to receive an electric detonator, a length of filament tape covering said well and secured to said explosive charge on either side of said WelL'said filament tape having a slit therein positioned immediately over said well, said slit being parallel to the direction of the longest filaments in said length of filament tape.

2. An explosive assembly comprising an explosive charge containing a well, a length of filament tape covering said well, said tape having a layer of adhesive and a layer comprised of a plurality of filaments disposed in a direction parallel to the edges of the tape, said tape having a slit therein positioned parallel to the direction of the longest filaments, the ends of said length of tape being adhesively secured to said explosive charge so that the slit in. said tape lies immediately over the well in said charge.

3. An explosive assembly comprising an explosive charge containing a well adapted to receive a detonating .means, two parallel lengths of filament tape having a layer of adhesive and located in juxtaposition covering said well and adhesively secured to the explosive charge, the side juncture of said lengths of filament tape lying across the diameter of said well.

4. A blasting assembly comprising an explosive charge containing a well, a length of filament tape having a layer :of adhesive covering said well, the ends of said length of tape being adhesively secured to said explosive charge, said length of tape having a slit therein positioned parallel to the direction of the length of the longest filaments in the tape, an electric detonator positioned in said well and having leg wires extending through said slit in said tape, said detonator secured against outward disengagement from said explosive charge by the portion of filament tape positioned over said well.

5. A blasting assembly comprising an explosive charge containing a well, two lengths of filament tape having a .layer of adhesive and located in juxtaposition covering said well and adhesively secured to the explosive charge, the side juncture of said lengths of filament tape lying across the width of said well, an electric detonator in said well having leg wires extending through the juncture of said lengths of tape, said detonator being secured in said well against outward disengagement with said explosive charge by said lengths of filament tape.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain 1898 

1. AN EXPLOSIVE ASSEMBLY COMPRISING AN EXPLOSIVE CHARGE CONTAINING A WELL, SAID WELL BEING OF A SIZE TO RECEIVE AN ELECTRIC DETONATOR, A LENGTH OF FILAMENT TAPE COVERING SAID WELL AND SECURED TO SAID EXPLOSIVE CHARGE ON EITHER SIDE OF SAID WELL, SAID FILAMENT TAPE HAVING A SLIT THEREIN POSITIONED IMMEDIATELY OVER SAID WELL, SAID SLIT BEING PARALLEL TO THE DIRECTION OF THE LONGEST FILAMENTS IN SAID LENGTH OF FILAMENT TAPE. 